Solar Cinema

With solar maximum just around the corner, the Sun is putting
on a show that rivals the most sizzling Hollywood thrillers.
Powerful solar flares and coronal mass ejections happen almost
every day. You can't see them with the naked eye, but the European
Space Agency and NASA have a front row seat, thanks to the Solar
and Heliospheric Observatory (SOHO). SOHO monitors solar activity
from a permanent vantage point 1.5 million kilometers ahead of
the Earth in a halo
orbit around the L1
Lagrangian point. Unlike an Earthbound observer, it can see
the Sun 24 hours a day.

On January 18, 2000, SOHO spotted a spectacular prominence,
pictured above in an animation spanning a 24 hour period. At
maximum, the prominence was about 100 times wider than the Earth.

Prominences are loops of magnetic fields with hot gas trapped
inside. Sometimes, as the fields become unstable, the they will
erupt and rise off of the Sun in just a few minutes or hours.
Beautiful prominences like these become more common as we approach
solar maximum.

Parents and Educators: Please visit
Thursday's Classroom
for lesson plans and activities related to this story.

When will the solar maximum actually take place? Recent work
by David Hathaway, a solar physicist at the Marshall Space Flight
Center, and his collaborators indicate that the solar activity
will peak around the middle of the year 2000.

"Our predictions have consistently targeted 2000
as the beginning of solar maximum," said Hathaway in a recent
interview, "but the latest numbers suggest that the peak
sunspot count in 2000 will be a bit lower than expected. The
projected peak is comparable to, but lower than the peaks of
the last two maxima (in 1989 and 1978). That would put all three
of the recent sunspot maxima in the same class -- above average
compared to all the sunspot cycles since the mid 1700's."

Above: By combining data about geomagnetic
activity during the previous solar cycle with sunspot counts
for the current cycle, David Hathaway and collaborators are able
to predict when the next sunspot maximum will occur. [Click
here for details]. According to their results, the sunspot
number -- and other forms of solar activity -- will peak beginning
in mid-2000. The dotted lines above and below the solid curve
line indicate the prediction curve's range of error.

"The sunspot maximum is usually a broad peak. There is a
two or three year period when activity is quite high. I expect
solar activity to be highest in 2000 and 2001, and then in 2002
it may decline back to where we [were] in 1999."

During this period of heightened solar activity, the Sun puts
on a nearly non-stop show. For instance, just one week ago SOHO
captured another sequence of prominences. This time, the Extreme Ultraviolet
Imaging telescope was observing in a mode with a higher-than-usual
telemetry rate, due to the fact that the Large Angle Spectrometric
Coronagraph (LASCO)
instrument had its doors closed in anticipation of spacecraft
maneuvers. The resulting movies (click on the image for a Quicktime
animation) are awesome. If eruptions like these are directed
toward the Earth they can cause a significant amount of aurora
and other geomagnetic activity.

For more information about space weather see http://SpaceWeather.com.
SOHO (the Solar and Heliospheric Observatory) is a mission of
international cooperation between NASA and the European Space
Agency. It is managed by the Goddard Space Flight Center for
the NASA HQ office of Space Science.